wife's Toyota V6 has the "maintenance free" battery but the eye glass is showing red which says "add distilled water" So I tore off the maintenance free sticker and unscrewed the cell caps and added about a 20oz distilled water. Now it is on the charger at 10 amps for 15 minutes then 2 amps until the charge gauge is at or near zero. The cells are bubbling nicely now and there were no dry cells